Typically, a total amount of toner an electrophotographic image forming apparatus can transfer or fix onto a recording medium such as paper or the like is known to have a limit. Amounts of toner transferred beyond that limit cause defective fixation or transfer.
Under-color removal, which reduces cyan (C) toner, magenta (M) toner, and yellow (Y) toner and replaces them with black (K) toner, is known as a method of reducing the total amount of toner. However, when the C toner, M toner, and Y toner are reduced, image quality deteriorates.
Japanese published unexamined application No. 5-265287 (JP-H05-265287-A) discloses reducing the clear toner without reducing the C toner, M toner and Y toner to reduce the total amount of toner.
However, when security letters and barcodes are formed with the clear toner, they cannot be identified if the clear toner is reduced as JP-H05-265287-A discloses. On the other hand, when the clear toner is reduced in printed images including background patterns and paper designs formed of the clear toner, there is no serious problem because they are visually identifiable. In this case, it is preferable to precisely reproduce colors without reducing the color toners. Namely, it is necessary to determine whether to clarify images formed of clear toner or precisely reproduce image colors formed of color toners, based on image classification. However, JP-H05-265287-A does not disclose such image classification-based control.
Accordingly, a need exists for an image forming apparatus capable of determining whether to clarify images formed of the clear toner or precisely reproduce image colors formed of color toners, based on image classification.